Sol-gel derived CuCo-oxide coatings as solar selective surfaces, synthesized onto aluminium substrates at various annealing temperatures, are analysed by correlating their structural, chemical bonding states, and surface morphological topographies. As the annealing progressed, all the coatings displayed a Cu0.56Co2.44O4 (ICSD 78-2175) phase with preferential orientation along (400) reflection plane. Rietveld refinement of X-ray diffraction (XRD) data indicate that residual stress and microstrains developed around the coating surfaces are reduced resulting in mechanically stable thin films. Enhancement of the crystallite size and preferred orientation of the surface were confirmed via XRD, field emission scanning electron microscopy (FESEM), and atomic force microscopy (AFM) analysis. X-ray photoelectron spectroscopy (XPS) analysis shows tetrahedral, octahedral and mixed states of Cu and Co ions with a stable atomic ratio of Co/Cu, and an increase of O and C contents but no metal-carbon bonding on the surface of materials. Optical reflectance investigations indicated that solar selectivity of the coatings increased from 3.81 to 24 as the annealing temperature reached up to 500 °C.
Abstract:
The use of economic resources enjoyed Iraq by especially oil resources, which constitute the main source of financial revenue, would the economic surplus outside the oil sector increases by mobilizing and rallying the labor power and turn it into an access capitalism, , was the cause of "the inaction of the productive sectors of the economy, made the investment planning process and even investment in human capital was not rationality with the increasing number of unemployed, particularly certificates and specializations high campaign, direction of the government towards market liberalism after 2003 through the, was focused not follow a clear economic policies, and the absence of planning
... Show MoreIn this work, HgBa2CaCu2-xSbxO8+δ compounds with (x = 0.2, 0.4, 0.6 and 0.8) have been prepared by the solid-state reaction method. Structural, morphological, and electrical properties were investigated using X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques. Using the 4-probe technique to study the effect of antimony-substitution for Copper on the electrical properties of HgBa2CaCu2-xSbxO8+δ (Hg-1212) phase was investigated by measuring the resistivity as a function of temperature. Results indicate that the addition of antimony (Sb) increases the volume fraction of the phase and changes the superconducting transition temperature Tc of the superconductor to a normal state. The dielectric loss factor and ac
... Show MoreBackground: Periodontal pathogens can induce free radicals over-formation and thus may cause collagen and periodontal destruction. Anti-oxidants are used as supplements to counteract the over production of free radicals in periodontal disease, that can reduce of collagen destruction. Coenzyme Q10 serves as an endogenous antioxidant, regenerates other antioxidants, stimulates cell growth, and inhibits cell death. Because it is an antioxidant, coenzyme Q10 has received much research attention associated with periodontal diseases. Perio Q gel may possibly be effective as a topical agent and as an adjunct to scaling& root planing in treatment of gingivitis and chronic periodontitis. Aim of study:Determine the periodontal health status in a foll
... Show MoreIn his post colonial novel, In the Skin of a lion, the Canadian/Sri Lankan writer,
Michael Ondaatje is so interested in the term "Post colonialism" because he wants to show
that the term doesn't only refer to a period of time that comes after colonialism. In other
words, post colonialism is not only referred to as a literal description of formerly colonial
societies. He deals with the termas a literary genre and an academic construct that describes
the global conditions of a man after a period of colonialism. He shows that post colonialism is
a theory that tries to examine and explore the different styles and faces of European authority
to control the colonized. Ondaatje's attempt through such term is to unmask Europ
This study examines the causes of time delays and cost overruns in a selection of thirty post-disaster reconstruction projects in Iraq. Although delay factors have been studied in many countries and contexts, little data exists from countries under the conditions characterizing Iraq during the last 10-15 years. A case study approach was used, with thirty construction projects of different types and sizes selected from the Baghdad region. Project data was gathered from a survey which was used to build statistical relationships between time and cost delay ratios and delay factors in post disaster projects. The most important delay factors identified were contractor failure, redesigning of designs/plans and change orders, security is
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